As human beings, we often trip over the same stone twice. I invite you to visit the US-Mexico border where we just keep tripping.

Science and common sense keep telling us that in poisoning our environment, we also poison our children, our grandchildren, and ourselves. The hundreds of factories called maquiladoras that have proliferated along the border have turned the area into one of the most polluted place on earth.

I have written about this subject before, but with meetings in Miami this month that aim to spread these shameful conditions on the border throughout Latin America with an agreement called the Free Trade Area of the Americas (FTAA), the topic has even more urgency.

Imagine you still live in Guatemala, Colombia, Argentina or whatever country you and your family came from and that your seven-year-old daughter is playing just outside your home. She trips and falls into a ditch where a neighboring jewelry-manufacturing maquiladora illegally dumps and burns toxic waste with total impunity. By the time the girl is rescued, she has second and third grade burns on her legs.

This tragedy took place two years ago in the Mexican border city of Reynosa, and the actual victim was Sarahí Mendoza Alvarez. Since then, the girl has been suffered multiple reconstructive surgeries that were supposed to allow the normal growth of one of her legs. But what hurts the most to the Mendoza Alvarez family is not the medical bills they can hardly afford.

To them, the impunity that the authors of this crime of negligence enjoy has been much harder to swallow. Maquila Works S.A. -that's the name of the factory- and its owner -Edward Pichirillo- continue poisoning Sarahí's neighborhood without any accountability. The family reported the incident to the authorities, but since then have been lost in a bureaucratic maze incapable of administering justice.

The Attorney's General's Office -which "misplaced" crucial documents submitted by the family- exonerated Maquila Works from any wrongdoing; and the Municipal Ecology Department -which now claims not knowing anything about the case- advised them "to give up on their legal complaint."

"This case frustrates me enormously," says Omeheira López, director of the NGO assisting Sarahí and her family, "because the victim is an innocent girl. Official corruption and impunity cause very regrettable damages."

These injustices are emblematic of the maquiladora industry all along the border, where millions of people live exposed to deadly poisons and are victims of lax labor practices.

The governments of United States, Canada and Mexico promised that the North American Free Trade Agreement (NAFTA) would either reduce or eliminate these injustices. Sarahí is one of the thousands of pieces of evidence that those promises were hollow. In fact, the Bush Administration, currently pushing the FTAA, essentially an expansion of NAFTA, puts communities like that of Sarahí at risk throughout the hemisphere.

Regardless of that, the governments of 34 Latin American countries still want their own NAFTA, and their ministers will hold a new round of FTAA talks to be held this month in Miami. The accord aims at turning almost the entire hemisphere into an immense open market.

What these negotiators won't tell you is that the accord would bring corporate impunity and environmental injustice from the US-Mexico border to all of the Americas.

But Latin Americans have started to express serious doubts about the FTAA advantages. According to a Zogby poll conducted among 531 Latin American community leaders, more than half said the US would be the accord's main beneficiary.

In Brazil, the Latin American giant and US commercial counterpoint in the region, almost three quarters of those surveyed think Washington will be the pact's big winner.

Perhaps, if Latin Americans were asked if they wish to have Maquila Works as their neighbor after seeing Sarahi´s scars, few would like to trip on that same stone.

To receive more information about environmental injustices, write to the Sierra Club at ecocentro@sierraclub.org.

Javier Sierra is a Sierra Club columnist. The Sierra Club is America's oldest, largest and most influential grassroots environmental organization.